Numerous reports have been made on technologies for the formation of electrically conductive layers or wirings, which use copper as an electrical conductor, by a metal organic decomposition process (MOD process) or fine particle dispersion deposition process as a liquid process.
Processes for producing a series of articles with a copper firm formed thereon are proposed, for example, in Patent Documents 1 to 4. These processes are each characterized by applying a liquid mixture, which contains copper hydroxide or an organic acid copper salt and a polyhydric alcohol as essential components, onto one of various substrates, and heating the substrate at a temperature of 165° C. or higher in a non-oxidizing atmosphere. For use in such liquid processes, copper formate is disclosed as an organic acid copper salt, and diethanolamine and triethanolamine are disclosed as polyhydric alcohols.
Patent Document 5 contains a proposal on a metal paste, which contains fine silver particles and a copper-containing organic compound and can form a metal film of excellent solder heat resistance on an underlying electrode. As the copper-containing organic compound for use in the paste, copper formate is disclosed, and as an amino compound to be reacted with copper formate to prepare a paste, diethanolamine is disclosed.
In Patent Document 6, a proposal is made on a metal salt mixture for forming a metal pattern useful as a circuit. As components that make up the mixture, copper formate is disclosed as a metal salt in addition to organic components. As the organic components, diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine and morpholine are disclosed as organic solvents, and pyridine is disclosed as a ligand for the metal.
Patent Document 7 discloses a low temperature-degradable, copper precursor composition useful for the formation of electronic wirings or a like purpose. The composition contains copper formate and a 3-dialkylaminopropane-1,2-diol compound, both of which are thermally degradable at low temperatures after printing.
Disclosed in Patent Document 8 is a composition for forming a thin copper film. The composition contains copper formate and an alkanolamine, and is useful in the above-mentioned liquid processes. As alkanolamines, monoethanolamine, diethanolamine and triethanolamine are exemplified.